This invention relates to apparatus for converting mechanical motion into electric signals. More particularly, this invention is a new mechanical control assembly which is used in converting mechanical motion into electronic signals used to move graphic displays on a screen.
Certain currently used electro-mechanical devices for providing graphic displays on an electronic screen include a manually operated control ball. The movement of the ball is converted into a graphic display on an electronic screen by a linkage including mechanical, electrical, and optical elements. These devices are used, for example, in certain video games, computers, and also have industrial, commercial, and military applications.
Briefly described, this invention includes a manual control ball rotatable in any direction at variable speeds. A pair of perpendicular rotatable shafts each tangentially contact the control ball. Each rotatable shaft is formed with a pair of circumferential grooves which are axially spaced on opposite sides of the control ball-shaft contact point. The circumferential grooves provide inner bearing raceways. A pair of outer bearing rings with outer raceways surround each shaft at locations at which the inner and outer raceways form pairs of cooperating raceways. Sets of rolling elements are located in each cooperating pair of raceways.
Preferably each shaft is provided with a straight knurled end. An encoder disk is mounted on the knurled end. The encoder disk has a central opening formed by a plurality of circumferentially spaced notches defining a plurality of inwardly projecting fingers positioned to deflect slightly and grip the knurles tightly.